The present invention is related to a pneumatic tool, and more particularly to a muffling structure for pneumatic tool.
A muffler is mounted in a gas exhaust passage of a pneumatic tool for reducing the sonority produced by the high pressure gas quickly flowing through the passage. The muffler can be a muffling plate or socket having multiple perforations and made of copper by sintering. U.S. Pat. No. 5,878,568 discloses such a muffler. Another type of conventional muffler is made of nonmetal flexible muffling fiber. Such muffler is formed with a shape corresponding to the shape of the gas exhaust passage of the pneumatic tool and is embedded therein. Such muffler is able to slow down the exhaustion speed of the high pressure gas and reduce the noise. FIG. 1 shows such muffler.
Referring to FIG. 1, the muffling fiber 1 has numerous voids for the high pressure gas to pass therethrough. The voids are able to achieve muffling effect to a certain extent. However, such muffling fiber 1 still has some shortcomings in effect and manufacturing as follows:
1. The muffling fiber 1 is formed with a shape adapted to the gas exhaust passage 2. Generally, the muffling fiber 1 is cylindrical and has a considerable height. The muffling fiber 1 has an outer diameter slightly smaller than the inner diameter of the gas exhaust passage 2 for easily plugging the muffling fiber 1 into the passage 2. Accordingly, the muffling fiber 1 can hardly tightly contact with the inner face of the wall of the passage 2. When the high pressure gas goes from the interior of the pneumatic tool into the gas exhaust passage 2, the muffling fiber 1 can achieve muffling effect to a certain extent. However, a gap exists between the muffling fiber 1 and the wall of the passage 2. Therefore, the high pressure gas can go through the gap without muffling.
2. In order to achieve better muffling effect, the muffling fiber 1 must be enlarged to contact with the inner face of the wall of the passage 2 as tightly as possible. However, it will be harder to plug the muffling fiber 1 into the passage 2.
3. More importantly, the muffling fiber 1 occupies a room of the gas exhaust passage to achieve muffling effect. Accordingly, the high pressure gas going into the passage 2 will be interrupted and damped by the muffling fiber 1. As a result, the output torque of the pneumatic tool will be greatly reduced. This is also unsuitable for the driving structure of the pneumatic tool. In addition, the energy is wasted.
It is therefore a primary object of the present invention to provide a muffling structure for pneumatic tool, which not only is able to achieve best muffling effect, but also is able to minimize the negative affection on the output torque of the pneumatic tool.
It is a further object of the present invention to provide the above muffling structure for pneumatic tool, which has simple structure and is easy to manufacture and assemble.
According to the above objects, the muffling structure for pneumatic tool of the present invention is mounted at an opening of an exhaust end of gas exhaust passage of the pneumatic tool. The muffling structure includes a cock body having a body section. One end face of the body section is recessed to form a receptacle communicating with the gas exhaust passage of the pneumatic tool. At least one through hole is formed through a close end of the receptacle to the other end face of the body section to communicate the receptacle with outer side of the pneumatic tool. The muffling structure further includes at least one muffling fiber body plugged in the receptacle. The muffling fiber body is formed with multiple fine voids for the gas to pass through the muffling fiber body.
The present invention can be best understood through the following description and accompanying drawings wherein: